秸秆还田配施促腐菌剂对稻田土壤理化性质与微生物数量的影响

Effect of Straw Returning with Decomposing Inoculants to Soil Physico-chemical Properties and the Abundance of Bacteria and Fungi Community

【目的】本研究通过对一系列物理、化学性质和微生物数量的测定,综合评价秸秆还田配施促腐菌剂对土壤质量的改善效果。【方法】采用大田小区方式,在秸秆还田条件下,设置不同菌剂施用量,考察水稻冬翻系统土壤理化性质及微生物数量变化,并通过灰色关联度分析综合评价得出秸秆配施菌剂最佳施用量。试验设空白处理(CK)、常规施肥+秸秆不还田处理(RT)、常规施肥+秸秆还田+7.5 kg ha^(−1)菌剂处理(M1)、常规施肥+秸秆还田+15 kg ha^(−1)剂处理(M2)、常规施肥+秸秆还田+30 kg ha^(−1)菌剂处理(M3)和常规施肥+秸秆还田处理(ST)。【结果】秸秆还田配施菌剂有效提高了秸秆腐解率,秸秆腐解率比ST平均提升了53.49%。配施促腐菌剂改善了土壤理化性质、提高了土壤细菌真菌数量。但是菌剂处理对不同指标提升效果仍有差异。对比ST,仅M1显著提升0~20 cm土壤有效钾含量和20~40 cm土壤全磷、碱解氮、有效钾含量,分别提升了49.45%、19.80%、19.34%和25.65%。仅M3显著提升了0~20 cm土壤R_(0.25)(水稳性大团聚体数量)和真菌拷贝数,分别提升了16.34%和89.06%。M2和M3均显著增加了0~20 cm土壤MWD(平均重量直径)和GMD(几何平均直径),且以M3数值最高。M2和M3处理均显著提升了20~40 cm土壤R_(0.25)、MWD、GMD、有效磷和细菌基因拷贝数,除有效磷含量外,M3数值均为最高。采用灰色关联度分析,综合评价秸秆还田配施菌剂浓度的土壤改良效果,结果表明以M3处理效果最好。【结论】秸秆还田配施菌剂改善土壤质量的效果更好,且菌剂用量不同其效果各异,其中秸秆还田配施30 kg hm^(−1)微生物菌剂综合改善0~20 cm与20~40 cm土壤质量的效果最佳。

[Objective]Soil physical-chemical properties and the number of bacteria and fungi at different depths(0~20 cm and 20~40 cm)were investigated to comprehensively evaluate the effect of straw returning with decomposing microbial inoculants on paddy soil.[Method]A field experiment with six treatments,including check control without straw returning and fertilizer(CK),fertilization+no straw returning(RT),fertilization+straw returning+7.5 kg hm^(−1)decomposing inoculant(M1),fertilization+straw returning+15 kg hm^(−1)decomposing inoculant(M2),fertilization+straw returning+30 kg hm^(−1)decomposing inoculant(M3),and fertilization+straw returning(ST),was set up to determine the soil physical-chemical properties and the abundance of bacterial ang fungal community,in order to obtain a better decomposing inoculant dosage through the results of the gray correlation analysis.[Result]With the addition of decomposing inoculants,the straw decomposition rate was significantly enhanced by 53.49%on average.Compared with ST,only M1 significantly increased the content of available potassium by 49.45%in 0~20 cm soil,and total phosphorus,available nitrogen,and available potassium by 19.80%,19.34%,25.65%in 20~40 cm soil.Only M3 significantly increased R_(0.25) and fungi copies in 0~20 cm soil by 16.34%and 89.06%.M2 and M3 significantly enhanced MWD,GMD in 0~20 cm soil,and M3 was the highest.M2 and M3 also significantly increased R_(0.25),MWD,GMD,available phosphorus,and bacterial gene copies in 20~40 cm soil,and M3 had higher values than M2 except for available phosphorus.According to the results of the gray correlation analysis,M3 was the optimal choice to improve the soil quality among 6 treatments.[Conclusion]Straw returning with 30 kg hm^(−1)decomposing microbial inoculants was a better way to improve the soil quality both in 0~20 cm and 20~40 cm soil.